历史街区交通微循环优化的双层规划模型

为满足历史街区日益增加的交通需求, 利用街区内密布的街巷网络组织交通微循环, 建立了历史街区交通微循环优化的双层规划模型, 以提高干路畅通性与路网平均行程车速、缩短绕行时间和控制环境污染为优化目标, 以街区内街巷的通畅和历史遗存保护为约束条件, 构建上层模型, 采用用户均衡交通分配与借助TransCAD求解下层模型, 并选取开封市草市街历史街区进行实例分析。计算结果表明: 优化计算使干路平均饱和度可由0.69最多降至0.36;路网平均行程车速可由26.33 km·h^-1最多提升至28.87 km·h^-1; 街区内街巷平均饱和度可由0.07最多提升至0.37;绕行时间及环境污染得到控制。可见, 该模型的应用缓解了干路网络的交通压力, 提高了街区可达性及总体运行效率, 具有良好的交通效益和环境效益。

Bi-level programming model of traffic microcirculation optimization for historic district

In order to fulfill the increasing traffic demand of historic district, rich streets and alleys in the district were used to organize traffic microcirculation, and a bi-level programming model of traffic microcirculation optimization for historic district was built.The up-level model was built targeting on increasing the transit efficiency of trunk roads, increasing the average travel speed of road network, deceasing bypass time and controlling environmental pollution in the constraint conditions district unblocking and historical relics protection of streets and alleys.User equilibrium traffic assignment was used to solve the down-level model by using TransCAD.The historic district of Caoshi Street in Kaifeng was taken as an example to carry out case analysis.Calculation result shows that optimization calculation makes the average saturation of trunk road decease from 0.69 to 0.36 at most, the average travel speed of road network increase from 26.33 km·h-1 to 28.87 km·h-1 at most, the average saturation of streets and alleys in the district increase from 0.07 to 0.37 at most, and bypass time and environmental pollution are controlled.Obviously, the model application relieves the traffic pressure of trunk road network and improves district accessibility and overall operating efficiency, which has good traffic benefit and environmental benefit.